Vehicle-mounted snowplows are well known in the art and are in common use. These plows typically attach to the front bumper of a vehicle and are raised or lowered using a hydraulic lift mechanism. The angle of the plow blade relative to the vehicle's bumper is sometimes manually adjustable.
To install the typical snowplow, mounting brackets are initially affixed to the vehicle and thereafter the blade of the plow is fitted onto the brackets when the plow is to be used. To avoid having to repeat the time consuming installation process every time it snows, many people will leave the plow blade attached to the vehicle for extended periods. Even after the plow blade has been removed, the mounting brackets are usually left on the vehicle year-round.
In recent years, a trailer-type snow plow was invented (see U.S. Pat. No. 4,403,432 issued to Biance). The entire plow assembly is in the form of a single fixture that is designed to be connected to an existing rear-mounted receiver-type trailer hitch of the vehicle. The assembly can be quickly installed or removed and does not require the permanent installation of specialized brackets or other hardware on the vehicle. Once installed, the plow is towed behind the vehicle and can be raised or lowered using a manual or electric winch. The transverse angle of the plow blade (the angle of the blade relative to its direction of travel) may be changed using a manually-adjustable pivot mechanism.
During the plow blade installation process, the blade will normally be set at an angle relative to the front or rear of the vehicle. The blade must be set at an angle prior to plowing so that the snow will be pushed to the side during the plowing operation. For vehicles that have a fixed blade, the angle is set when the blade is mounted on the brackets. For vehicles that have an adjustable blade, the angle is set prior to the plowing operation and then it may be reset during the operation. Being able to vary the angle of the blade allows the operator to change the direction in which the snow is pushed. This greatly facilitates plowing around obstacles and allows greater flexibility when piling the snow about the area being plowed.
Certain problems still exist for users of prior art snowplows. The greatest problem involves the difficulty in changing the transverse or side-to-side angling of the plow blade prior to and during use to facilitate the plowing operation. Many operators avoid changing the angle of the blade since it may require the user to remove significant quantities of ice and snow from the area surrounding the pivot mechanism. In addition, the mechanism itself may become frozen due to icing of the pivot mechanism.
Therefore, changing the angle of the blade typically requires significant expenditures of time and effort. This is usually exacerbated by inclement weather at the time the user is employing the apparatus.
Another problem experienced by users of the prior art snow plowing apparatus is that the plow blade is usually inefficiently sized for the plowing conditions. A blade that is fairly small will cause the operator to have to make a larger number of traverses of the area to be plowed than would be required if a longer plow blade was being used. This problem is most noticeable when one wishes to use a small blade for plowing a driveway and a longer blade for plowing a parking area. In view of these considerations, the width of the plow blade may not be matched to the particular plowing operation.
It is therefore desirable to provide a plowing apparatus that does not succumb to the above-noted problems. The apparatus should include a plow blade that may be pivoted with little or no effort on the part of the user. The plow blade should also include a mechanism that enables a user to adjust the size of the blade to efficiently match the snow conditions. In addition, the apparatus must be capable of being rapidly deployed on or removed from a vehicle. It is furthermore desirable that the apparatus include a simple adjustment mechanism for the elevation of the plow blade.